| Studies of the layer-by-layer self-assembly for polyelectrolytes became popular after the original work of Decher in 1991.The The iterative, alternate adsorption of oppositely charged polyelectrolytes on the substrates is well-established as a method for the layer-by-layer assembly of multilayered polymer films. The methods and techniques in this area are gradually improved with the development in analytical instruments. These experimental methods are good at description of self-assembly process, the externality character of multilayer and its interior structure. But these methods are usually used to monitor the self-assembly process separately which is disadvantageous to the better understanding of self-assembly. The optical quartz crystal is very useful to describe the self-assembly multilayer and the quartz material is usually used in the quartz crystal microbalance (QCM). Thus, in the basis of mending structure and measurement of the piezoelectric sensors, in this thesis we report the combining technique of piezoelectric sensor and absorbance measurement. The main results were listed below.1. The electrode-separated piezoelectric sensor was used as measurement cell. The method to correct the influence of conductivity to the frequency of piezoelectric sensor was investigated. The prepared detection cell can be used for both piezoelectric sensor and absorbance measurement. It was shown by experimental results that the new piezoelectric-optical technique can carry out the real-time monitor of the dynamic process in the formation of the multilayer and the measurement of the absorbance of the multilayer. This technique was applied to monitor the adsorption of dye and surfactant and layer-by-layer self-assembly of anion/cation polyelectrolytes and polyelectrolyte /dye.2. The frequency–temperature characteristic of a QCM sensor can be adjusted by the cut angle of the quartz crystal wafers. It was shown that the frequency responses to mass and viscodensity are very close among the Y-rotated cut QCMs with the cut angles in the range of 35.15–35.7°. In a 9MHz QCM with a cut angle of 35.65°, the value of dF/dT was close to zero in water, which, in turn, to improve its detection limit in liquid phase. The applicability of the QCM in new cut angle was demonstrated in monitoring the alternate adsorption processes of polyelectrolyte and nanoparticle.3. Layer-by-layer self-assembly of polyelectrolytes and nanoparticles was monitored by QCM, the results demonstrated that the velocity of self-assembly of silver nanoparticles on the cationic polyelectrolyte (PDADMAC) films is decreased with the increase of time, the self-assembly of gold nanoparticles on the anionic polyelectrolyte(PSS) is similar to the silver nanoparticles system. The experiment proved that QCM is a useful technique in the study of dynamics of self-assembly.4.The adsorption behavior of polystyrene films was investigated by QCM, we compared the difference in the quantity and dynamics of adsorption between the normal polystyrene films and the porous polystyrene films. The results demonstrated that the adsorbed amount onto the porous film were much greater than those on the normal polystyrene film due to the larger area of porous films and the velocity of adsorption on to the porous polystyrene films are decreased. It was shown that the adsorption isotherms of surfactant on the polystyrene films followed Langmuir equation. This experiment demonstrated that QCM is a simple and useful method in the study of adsorption behavior of polymer films.
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